The present invention relates to a tactile switch and, more particularly, to a tactile switch enabled to increase the lifetime of a product, such as a click spring provided therein.
Such a kind of a related tactile switch is described hereinbelow with reference to FIG. 4.
As shown in this figure, a concave portion 3 is provided in a base 2 of a tactile switch 1. Stationary contacts 5 and 6 are disposed on the bottom face 4 of the concave portion 3. Terminals 7 and 8 to be fixed to a circuit board 9 are connected to the stationary contacts 5 and 6.
On the other hand, a circular click spring 10 is disposed over the top faces (that is, the right-hand-side faces, as viewed in this figure) of the stationary contacts 5 and 6 fixed onto the bottom face 4 of the concave portion 3. A circumferential portion of the click spring 10 is connected to the stationary contact 6. The central portion of the click spring 10 is formed in such a way as to be able to move upwardly and downwardly.
Thus, the central portion of the click spring 10 is provided in such a manner as to be always away from the stationary contact 5 disposed at the center of the bottom face 4 of the concave portion 3. Furthermore, a push button 11 is formed above the click spring 10 (at the right-hand side thereof, as viewed in this figure) in such a way as to be able to move freely upwardly and downwardly with respect to the bottom face 4 of the concave portion 3.
Further, the push button 11 is installed in such a manner as to be restrained by a cover 12 from moving sideways. Furthermore, an actuator 13 is provided on the bottom face of the push button 11. The actuator 13 and the push button 11 are formed from a synthetic resin.
When the push button 11 is depressed, the central portion of the click spring 10 is pushed through the actuator 13 so that the central portion of the click spring 10 descends toward the bottom face 4 of the concave portion 3 (that is, to the left-hand side thereof) and comes into contact with the stationary contact 5. Therefore, the stationary contacts 5 and 6 are electrically conducted to each other. Thus, the tactile switch 1 performs a switching operation.
However, since the push button and the actuator are formed from a synthetic resin having low elasticity, the pushing operation of the push button tends to give an excessive impact to the click spring. This causes decrease in the lifetime of the click spring and deterioration in the quality thereof.